Overexpression of Elsholtzia haichowensis metallothionein 1 (EhMT1) in tobacco plants enhances copper tolerance and accumulation in root cytoplasm and decreases hydrogen peroxide production

► Transgenic tobacco overexpressing EhMT1 showed higher tolerance to Cu. ► Plants expressing EhMT1 accumulated more Cu in soluble fraction of roots. ► The study provides the first cytochemical evidence of MT decreasing H2O2 accumulation.